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Nauka – Technika – Technologia : seria wydawnicza AGH. Tom 10
No full textOil-based drilling fluids are primarily used in challenging geological and reservoir conditions, such as high temperatures, high pressures, reactive rock formations, or the influx of mineralized formation water. This publication presents the results of laboratory tests on the rheological properties and stability of oil-based drilling fluid, with micronized barite as the weightening material. To enhance the stability of these drilling fluids, an organophilic nanomaterial – amino-attapulgite, was used. The research demonstrated that the combination of micronized barite and amino-attapulgite in oil-based fluids allows for the modification of their properties across a wide range of densities and low rheological values. The results showed that incorporating organophilic attapulgite and using micronized barite as the weightening agent reduces sedimentation conditions and improving stability drilling fluids.Płuczki na bazie olejowej stosowane są głównie podczas wiercenia otworów w trudnych warunkach geologiczno-złożowych, takich jak np.: wysoka temperatura, wysokie ciśnienia złożowe, występowanie reaktywnych formacji skalnych czy też dopływ zmineralizowanych wód złożowych. W publikacji przedstawiono wyniki laboratoryjnych badań parametrów reologicznych oraz stabilności płuczki wiertniczej na bazie olejowej, gdzie jako materiał obciążający zastosowano mikronizowany baryt. W celu poprawy stabilności tych płuczek stosowano organofilny nanomateriał, jakim był amino-atapulgit. W wyniku przeprowadzonych badań wykazano, że zastosowanie mikronizowanego barytu w połączeniu z amino-atapulgitem w płuczkach na bazie olejowej pozwala na modyfikację ich właściwości technologicznych w szerokich zakresach ciężaru właściwego i niskich wartościach właściwości reologicznych. Na podstawie uzyskanych wyników badań stwierdzono, że włączenie organofilnych atapulgitów do płuczek wiertniczych na bazie olejowej oraz zastosowanie mikronizowanego barytu jako materiału obciążającego ogranicza sedymentację barytu, a także poprawia stabilność takich płuczek.Krakówrozdziałwersja wydawnicz
Documentation and Assessment of Geosites for Geotourism and Geoparks
No full textThe e-textbook is a comprehensive academic study that discusses the fundamental principles of documenting and assessing geoheritage. It focuses on the protection, promotion, and access to geosites, and issues related to geotourism such as the design of geoparks, geotourism attractions, and geotourism products according to sustainable regional development principles. The terminology related to geoheritage is clarified, and methods and tools for geoeducation are outlined. The e-textbook also explores the management of geosites for scientific, educational, and economic purposes. It was developed by a team from the Department of General Geology and Geotourism at the WGGiOŚ AGH University of Krakow in collaboration with employees from domestic and foreign geoparks. This resource is meant for students, teachers, tourist guides, as well as professionals involved in the promotion, management, and regional development of geosites.ebooke-podręczni
Opuscula Mathematica
No full textIt is known that the discrete matrix Riccati equation has the order preserving property under some assumptions. In this paper we formulate and prove the converse statement for the case when the dimensions of the matrices are and the order preserving property holds for all such symmetric matricesKrakówwersja wydawnicz
Geology, Geophysics & Environment
No full textSeismic and rockburst hazards represent significant challenges during the longwall mining of coal seams. One analytical approach to assess the potential for rockburst hazards involves reconstructing the stress conditions within the rock mass. This article reports on the findings from three-dimensional (3D) numerical modeling aimed at examining the distribution of maximum shear stress within the rock mass amid the longwall mining operations of the 703/1 coal seam in a mine situated in the Upper Silesian Coal Basin, Poland which was disrupted by a rockburst incident. On the day of the rockburst, substantial concentrations of maximum shear stress were identified in a thick sandstone layer proximate to the boundary of the overlying 624 coal seam located significantly above the 703/1 coal seam. The calculated maximum shear stress demonstrated an increase of approximately 80% over the values observed in the absence of edge effects. Furthermore, also higher concentration of maximum shear stress was identified within the geologically weaker strata adjacent to the 703/1 coal seam. These observations facilitated the classification of the examined rockburst as a stress-stroke phenomenon. Additionally, the study determined the spectral parameters of the tremor, which possessed an energy of 9.8 × 10 J and triggered the analyzed rockburst. The ratio of the seismic energy of S and P-waves confirmed a shear mechanism in the focus. The scope of inelastic deformation within the focal zone was also quantified. Following the event, the rock mass that had been destressed due to the significant tremor and subsequent rockburst exhibited reduced seismic activity upon the resumption of longwall mining of the 703/1 coal seam.Krakówwersja wydawnicz
Journal of Casting & Materials Engineering
No full textThe goal of the cooling procedure after austenitizing in the austempering heat treatment process applied to ausferritic ductile iron (ADI) castings is to rapidly reduce the temperature throughout the casting volume to the temperature range of the process window in which the proper metal matrix structure is formed. The lower limit of this range must be higher than the temperature at which the martensitic transformation starts. The upper limit is selected to eliminate the possibility of diffusion decomposition of austenite while holding castings at austempering temperature. Most often in heat treatment practice, salt baths are used for this purpose. Such a solution makes it possible to realize in one device both the procedure of cooling down to a given temperature and the procedure of isothermal heat treatment at this temperature. Unfortunately, the presence of molten salt in the process equipment has a very unfavorable impact on working conditions and ecology. The purpose of this research is to analyze the possibility of replacing the salt bath cooling procedure in the manufacturing process of ADI castings with a water mist spray cooling procedure on the surfaces of the heat-treated casting. If such cooling is effective, subsequent procedures of heat treatment operations can be carried out with traditional furnace equipment without the use of molten salt, which will clearly improve the environmental performance of the enterprise. The article, using analytical and numerical methods, analyzes the possibility of cooling objects made of cast iron with the help of a high-efficiency heat receiver such as water mist spraying. The limiting conditions for carrying out the process for the assumed cooling curve were considered. It was proposed to use a PID controller realizing the function of controlling the intensity of water mist spray, which corresponds to the intensity of the heat flux received from the heat-treated casting. The theoretical analysis carried out allows us to conclude that water mist cooling according to the assumed cooling curve is practically feasible.Krakówwersja wydawnicz
Geomatics and Environmental Engineering
No full textAlong with the concepts of “smart city” and “digital twin,” the 3D (three-dimensional) city models have started to be used as a basis for many studies that have been carried out in recent years. The most important and basic components of 3D city models are the structures that are located in the cities. However, some small structures of historical importance are within the category of the buildings in a city but are often not as large as a building. Historical fountains are some of these structures. For this reason, modeling with existing 3D city model-production methods is a little more complicated and requires local measurements and detailed modeling studies. As a result, this study has designed a database scheme design in which the historical city wall fountains in Istanbul can be stored in a spatial database and modeled in three dimensions (with procedural modeling when necessary). In addition, the conveniences that this infrastructure will provide in the production of 3D structure models and some difficulties that were encountered during these studies are also discussed and examined.Krakówwersja wydawnicz
Geomatics and Environmental Engineering
No full textThis research aims to investigate the morphodynamics of the Wulan River estuary in Demak Regency using the integration of multispectral remote sensing images and numerical modeling. In this study, PlanetScope for a manual-visual analysis of estuary morphodynamics and Sentinel-2 MSI Level 2A to obtain periodic total suspended solids (TSS) information for the east and west monsoon seasons. MIKE by DHI software used to develop hydrodynamic numerical modeling in order to characterize the current circulation and sediment transport model. Based on a marine cartography aspect, the obtained results illustrated that the climatological phenomenon of seasonal forcing plays a role in the development of the current circulation and indirectly influences the sediment transport. During the west season, the morphodynamics in the Wulan River estuary are much more massive and significant as compared to the east season. A projection of the deposition that results from the sediment transport is described in the bed-thickness change, this occurs in the western part of the Wulan River estuary during the east season, while the bed-thickness change occurs predominantly in the northern part during the west season (where there was previously a beach sandbar phenomenon). This was verified through multi-temporal satellite imagery that the deposition that occurs in the northern part of the Wulan River estuary during the west season is increasingly progressive and massive.Krakówwersja wydawnicz
Computer Methods in Materials Science
No full textThe article describes a functionally graded porous material in an application for sandwich beams. The bending and vibration behaviors of this structure are studied using the finite element method based on a simple beam model. The influences of some parameters, e.g., the porosity factor or the exponent graded, are also studied in this article. Finally, the numerical results are presented with some discussion.Krakówwersja wydawnicz
Energy Conversion and Management
No full textThis study focuses on the use of car tyre waste collected at a tyre repair station in Krakow (Poland). Waste from damaged tyres is disposed of as municipal solid waste. Therefore, the management of waste tyres already shredded by pyrolysis at 500 °C has been proposed. Tyre waste was hypothesised to be converted into valuable chemical products by pyrolysis in a hybrid reactor (drop-tube–fixed-bed reactor). On a micro scale, pyrolysis–gas chromatography–mass spectrometry was used to analyse the pyrolysis process. It has been shown that the formation of aromatic hydrocarbons during pyrolysis clearly depends on whether the catalyst and tyre waste are mixed together or arranged in layers. Since the layered arrangement favoured the formation of hydrocarbons, such a system was used in the drop-tube–fixed-bed reactor. The high heating rate (500 °C/s) of tyre particles in the drop-tube–fixed-bed reactor at 500 °C allowed for the obtained a raw carbon black yield of 40.8 %. A similar yield of raw carbon black determined by thermogravimetric analysis for a heating rate of 0.17 °C/s) was observed at 800 °C. However, before commercial use, raw carbon black requires demineralisation because of its high ash content (approximately 50 %). The raw carbon black ash contained up to 90 % , indicating that it could be a valuable catalyst material. Pyrolysis of tyre waste over the catalyst reduced the oxygen content in the oil and yield. The oil yields of tyre pyrolysis without a catalyst and over zeolite Y were 38 wt% and 35 wt%, respectively. The main components identified in the tyre pyrolysis gas were methane (27.6%), ethene (28.8%), and hydrogen (15.6%). The gas from catalytic pyrolysis was richer in CO and .postprin
Geology, Geophysics & Environment
No full textIn recent decades there has been growing evidence of the impact of ongoing climate warming on the frequency of rockfalls. However, these are not adequately documented, especially in non-glaciated, high mountain regions of middle latitude. This study comprehensively documents the Turnia Kurczaba rockfall, one of the most significant rockfalls recorded in recent decades in the Tatra Mountains. The precise projections of the volumes and distribution of rock losses and deposits, the determination of the trajectories, modes and speeds of movement of rock material, as well as information on the geological, morphological, and meteorological conditions behind the Turnia Kurczaba rockfall form a unique dataset. The data documents a spectacular episode in the contemporary development of a complex slope system in the Tatras in an all-encompassing way and can be used to validate and calibrate existing models and improve numerical simulations of other rockfalls, both for hazard and risk assessment and slope evolution studies. Moreover, in the context of archival data, they demonstrate that in the Tatra sporadic permafrost zone, only relatively small rockfalls have been recorded in recent decades. Their cause was not the degradation of permafrost but freeze-thaw processes with the co-participation of rainwater and meltwater. The largest of these occur within densely fractured cataclysites, mylonites, and fault breccias. The impact of rockfalls on the morphodynamics of talus slopes is uneven in the storied arranged rock-talus slope systems. Even colluviums belonging to the same slope system can differ in their development rate and regime, and different thermal and wetness drivers can control their evolution.Krakówwersja wydawnicz